Activist investor Elliott Management Corp. has raised its stake in German energy company Uniper SE (UN10.XE) to 17.84% from 16.51%, according to a regulatory filing. Uniper's largest shareholder, Finnish state-controlled Fortum Oyj , is currently barred from holding more than half the shares by Russian authorities, due to some Uniper activities in the country. But if circumstances change, Fortum could potentially launch a takeover bid and buy out minorities, such as Elliott...